Miscut device for flying shears with a continuous drive



United States Patent Walter Waldura Inventors:

Priority:

MISCUT DEVICE FOR FLYING SHEARS WITH A CONTINUOUS DRIVE Primary Examiner James M. Meister An0rney John J. Dennemeyer ABSTRACT: A miscut device for flying shears with an oscillating shears frame mounted on a main crankshaft whose eccentrics guide the upper knife support downwardly during each forward movement of the shears frame for the cutting action while the lower knife support connected by push rods to 2 Claims 2 Drawing Figs non-rotating miscut eccentrics of the main crankshaft is US. Cl. 83/304 guided upwardly for the cutting action by selectively reversing Int. Cl. B26d 1/56 these eccentrics, whereas in the lower dead center position of Field of Search 83/304, the miscut eccentrics the cutting knives no longer meet to 305, 315, 316 produce a cutting action.

8 9 o o 20 20c 11 T77 i W H Patented Aug. 4, 1970 3,522,751

Sheet 1 of 2 FIG] Patented Aug. 4, 1970 3,522,751

Sheet 2 of2 U.S. PATENT 3,522,751 MISCUT DEVICE FOR FLYING SHEARS WITH A CONTINUOUS DRIVE This invention relates to a miscut device for flying shears provided with a continuous drive including oscillating shears frames carrying the upper knife, and a lower knife support guided in the shears frames for cutting travelling sheets or strips, for example metal sheets or strips, and is a further development and improvement of a known construction comprising a quick adjustment unit, for example a compressed air cylinder, by means of which eccentrics may be shifted between two dead center positions which vary by 180, and which are disposed in eyes of connecting rods of the lower knife support on the crankshaft of the main drive unit. In the case of this known miscut device selectively controllable miscut eccentrics are rotated in the upper eyes of the connecting rods of the lower knife support, while the miscut eccentrics as well as the quick adjustment unit are journalled in the lower knife support itself or are supported by it.

When the miscut eccentrics are moved into the one dead center position the lower knife support comes into a downwardly displaced position relative to the upper knife, in which the cutting knives no longer engage during the cutting stroke.

At high travel speeds, i.e. at a high frequency of the oscillating motions of the flying shears the acceleration and delay powers to be furnished or absorbed by the oscillating drive become bigger with the increase of the oscillating masses. As the known miscut device is arranged on the lower knife support which follows the oscillating motion, it raises this oscillating mass in the sense that with high travel speeds and thus with high oscillating frequencies the drive elements may be damaged.

Flying shears are known which have a miscut device on which the lower eyes of the connecting rods of the lower knife support are connected to miscut eccentrics, which are rotatably mounted on a straight central portion of the crankshaft of the main drive unit and which are driven over an intermediate shaft by means of gears independently of the main shaft. (US. Patent 2,327,106). In this arrangement the miscut eccentrics may be driven relative to the constantly rotating main shaft at different transmission ratios, so that the number of miscuts between two cuts is obtained and may be adjusted by these transmission ratios. For a permanent setting of the miscut eccentrics in a dead center position, in which the cutting knives no longer make a cut, the self-drive of the eccentrics may be disconnected in that the intermediate shaft is stopped in a predetermined position by operating a clutch. If the clutch is engaged again for the cutting action, this produces also high acceleration powers, because the clutch can only be a dog coupling due to the rigid principle of the knife motions to each other. Therefore one has abandoned this earlier construction and adopted a widely known arrangement with interengaging, additive eccentrics but this meant giving up the advantage of selective control of the miscuts and required a more complex construction.

It is an object of the invention to provide flying shears provided with a selective controllable miscut device, in which the miscut device no longer causes a higher stress of the drive elements of the shears by its presence or by its function, as it is the case for the two prior art selectively controllable miscut devices described above. In one case an excessive head weight of the oscillating frame work of the shears, in the other case a control clutch in the train of the drive elements of the miscut device are to be avoided. Surprisingly this problem can be solved by a combination of features of the miscut devices which are known to be unfavorable with respect to stress requirements in that a. themiscut eccentrics are arranged inside of the lower eyes of the connecting rods of the lower knife support and are pivotally mounted on a straight, central portion of the main drive crankshaft b. the miscut eccentrics are selectively reversible by a quick change unit exclusively between two dead center positions.

In this way the quick change unit as well as the miscut eccentrics become stationary, respectively are withdrawn from the swinging mass, whereby all shifting clutches are avoided. Flexible piping to supply the necessary energy to a co-oscillating quick change unit, as well as the adjustable drive for the miscut eccentrics may now be designed as heavy as desired.

All these advantages result from the inventive combination of the features mentioned above, which in the arrangement in which they are known, produce exactly those disadvantages which have to be eliminated according to the object of this invention.

In view of the fact that the miscut eccentrics are all reversible and no longer rotate continuously to make the cuts, the upper edge of the lower knife executes purely rotary motions, which may be adjusted to two different levels. However the shears operate normally such that at least one miscut occurs between two cuts, so that the lower knife support goes to the lowest level after each cut and cannot make scratches on the lower side of the strip. Only in the case where short samples are to be cut from the strip two cuts will be made with immediately successive oscillating motions of the shears without actuating the miscut device. In this respect it is not objectionable that the lower knife moves along the strip at the higher level during the return oscillation of the shears, since the sample is wasted anyway.

The known construction with different numbers of revolutions of the miscut eccentrics provides that-the bigger the intervals are at which the knives meet for a cut the lower knife is displaced downwardly after a cut at each oscillation of the shears only by a small partial interval or is displaced upwardly before a cut, so that in this case there is greater danger that the lower knife touches the strip.

The attached drawings show an embodiment of flying shears provided with a miscut device according to the invention, wherein;

FIG. I is a vertical section through the frame of the shears and the main drive-shaft, and

FIG. 2 is a horizontal section through the main drive-shaft with a partial section through the eccentric shaft which produces the oscillating motions of the shears frame.

The main element of the flying shears is the oscillating frame 1, consisting of two lateral cheeks 2,2 between which the upper knife support 3 is clamped by means of a long bolt 4. The cheeks 2,2 are clamped at their lower ends by another long bolt 4a, by which the frame 1 is closed. The upper knife 5 is mounted in the upper knife support 3 and cooperates with the lower knife 6 in the lower knife support 7. The lower knife support 7 is guided with a sliding motion in the shears frame 1.

The cutting strokes are carried out exclusively by the upper knife 5 in that the cheeks 2,2 are mounted on eccentrics 8a,8a of the main drive crankshaft 8. This main drive crankshaft 8 is mounted in two external bearing blocks 9,10, as well as in two inner bearing blocks 11,11.

The swinging motions of the shears frame 1 are guided by an eccentric shaft 15 displaced relative to the main drive crankshaft 8 laterally and vertically. This eccentric shaft 15 has two eccentrics 16 whose eccentric stroke is transmitted by swinging arms 17,17 to the lower ends of the cheeks 2,2. The arms 17,17 are linked to the cheeks 2,2 by hinge bolts 18,18.

The miscut device according to the invention consists of two eccentrics 20,20 which are pivotally mounted on straight central portions of the main drive crankshaft 8. These miscut eccentrics 20 are mounted in the lower eyes of push rods 21,21, which are linked by bolts 22,22 to the lower knife support 7. Over gear wheels 19,19 of an intermediate shaft 23 which meshes with teeth 20a,20a of the miscut eccentrics 20,20, the miscut eccentrics are normally kept from rotating. They may be adjusted only between an upper and a lower dead center position, for which purpose the intermediate shaft 23 carries a pinion 24 which engages a rack 25 at 28. In the embodiment illustrated a quick change unit, for example a compressed-air cylinder 26, is connected with its connecting bolt 27 to this rack 25 in a flexible manner at 28.

In the embodiment shown the miscut eccentrics 20,20 are located in a lower dead center position Accordingly, the lower knife support 7 with its lower knife 6 has moved to a lower level in that the cutting knives 5,6 no longer meet for a cut with the cutting strokes effected by the eccentrics 8a,8a. In this position of the miscut eccentrics 20,20 any desired number of miscuts may be made. In order to reverse the miscut eccentrics 20,20 to the upper dead center position displaced by 180, the compressed-air cylinder 26 is put under pressure whereby the shaft 23 turns over the adjusting rack and the pinion 24. This rotation of the shaft 23 acts over the gear wheels 19,19 on the miscut eccentrics 20,20 in the above described sense.

The two central bearing blocks 11 of the "main drive shaft may also be located further outwardly and in some cases may be omitted so that the two miscut eccentrics 20,20 are combined into a sleeve with two laterally joined miscut eccentrics. With this arrangement a tooth system on the sleeve is sufficient to provide a direct or indirect connection to the rack 25 of the quick displacement unit, so that the long intermediate shaft 23 may be omitted.

We claim:

1. A miscut device for flying shears of the type including a main crankshaft having a straight portion, a shears frame mounted for oscillating movement on said main crankshaft, an upper knife support having an upper knife mounted on said oscillating shears frame and a lower knife support having a lower knife guidably mounted for reciprocating movement in said shears frame and operatively associated with said upper knife support for cutting strip material continuously advanced through said flying shears the improvement which comprises. at least one miscut eccentric mounted on said main crankshaft straight portion for rotary movement between an upperdead center position with said upper and lower knives in strip material cutting relationship during'the cutting stroke of said flying shears and a lower dead center position for maintaining said upper and lower knives out of said cutting relationship during said cutting stroke, a push rod having a lower eye for receiving said miscut eccentric for operatively connecting said miscut eccentric to said lower knife support and a quick change power unit operatively connected to said miscut eccentric for selectively moving said miscut eccentric into said upper and lower dead center positions.

2. A miscut device in accordance with claim I wherein a pair of said miscut eccentrics are provided, said miscut eccentrics being arranged in longitudinally spaced relationship on spaced portions of said main crankshaft, and a pair of said push rods connected to said miscut eccentrics and to said lower knife support and wherein said quick change power unit is operatively connected to both of said miscut eccentrics. 

